load cell output can be directly applied to the differential
inputs of ADS1242.
APPLICATION EXAMPLES
GENERAL-PURPOSE WEIGHT SCALE
HIGH PRECISION WEIGHT SCALE
Figure 8 shows a typical schematic of a general-purpose
weight scale application using the ADS1242. In this ex-
ample, the internal PGA is set to either 64 or 128 (depending
on the maximum output voltage of the load cell) so that the
Figure 9 shows the typical schematic of a high-precision
weight scale application using the ADS1242. The front-end
differential amplifier helps maximize the dynamic range.
2.7V ~ 5.25V
EMI Filter
VDD
ADS1242
GND
VDD
VREF+
EMI Filter
AIN0
DRDY
SCLK
DOUT
DOUT
CS
Load Cell
MSP430x4xx
or other
Microprocessor
SPI
EMI Filter
AIN1
MCLK
GND
XIN
XOUT
VREF–
EMI Filter
FIGURE 8. Schematic of a General-Purpose Weight Scale.
2.7V ~ 5.25V
EMI Filter
2.7V ~ 5.25V
VDD
VDD
VREF+
EMI Filter
RI
OPA2335
AIN0
Load Cell
RF
DRDY
SCLK
DOUT
DIN
MSP430x4xx
or other
Microprocessor
ADS1242
ADS1243
CI
SPI
RG
RF
CS
RI
OPA2335
EMI Filter
EMI Filter
AIN1
MCLK
GND
XIN
XOUT
VREF–
GND
G = 1 + 2 • RF/RG
FIGURE 9. Block Diagram for a High-Precision Weight Scale.
ADS1242, 1243
21
SBAS235B
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